The Candidate, a gastroenterologist/health services researcher has developed a focused research program in cancer prevention and control, primarily through the use of large population-based databases. In addition, he has mentored several trainees and junior faculty at different levels of training. However, because of time and budgetary restraints, his ability to provide data and methodological support to junior researchers is increasingly limited. In addition, he has been unable to expand his research focus to different cancer sites and other content areas, including pharmacoepidemiology. The proposed Established Investigator Award in Cancer Prevention, Control Behavioral and Population Research will assist the Candidate in fulfilling his long-term career goals. These include to evaluate the effectiveness of commonly performed screening, treatment and surveillance procedures in routine clinical practice; determine the accuracy, completeness and appropriateness of alternative methods to measure cancer screening, surveillance, and therapy; and develop a critical mass of cancer prevention and control researchers. The proposal will enable the Candidate to use data sources with which has considerable experience to study other clinically relevant issues. He will investigate the recognition of pre-malignant conditions of the esophagus and its impact on patient outcome, as well as the frequency of use and clinical impact of endoscopic ultrasonography on the diagnosis and treatment of patients with gastrointestinal cancer. In addition, we will develop expertise in the use of pharmacy databases to study the protective effects of non-steroidal anti-inflammatory drugs on colorectal cancer incidence. The resources of this award will also enable aim to develop an infrastructure that will provide the necessary data and research support to train junior investigators in the use of large databases to conduct cancer related health services research.